Inter-modal freight transport involves the transportation of freight via multiple modes of transportation (e.g., rail, ocean vessel, and truck) without any handling of the freight itself when changing modes. The advantage of using this method is that it reduces cargo handling, which in turn improves security, reduces damages and loss, and speeds transport.
Inter-modal freight is typically shipped via standardized containers, particularly when one of the modes of transport is aboard ship. Using standardized containers ensures interchangeability between different modes of transportation worldwide.
The standardized containers used for shipping inter-modal freight are known as “inter-modal” or “ISO” containers. The moniker “ISO” derives from the fact that the dimensions of the containers have been defined by the International Organization for Standardization (ISO). These containers are eight feet (2438 mm) wide by eight feet (2438 mm) high. The most common lengths are 20 feet (6096 mm) nominal, 40 feet (12192 mm), 48 feet (14630 mm) and 53 feet (16154 mm), although other lengths exist. The containers are made out of steel and can be stacked on top of each other.
Notwithstanding the many benefits of using inter-modal freight transport, intelligence analysts believe that there is a relatively high potential risk of inter-modal containers being utilized by terrorists to deploy WMDs on U.S. soil. This assessment is based on factors such as (1) the ease of use versus the relative difficulty of detection; (2) the relative security and reliability, from an operational perspective, of commercial maritime container transportation; (3) the adaptive behavior of terrorists to employ methodologies with the history of success consistent with achieving operational objectives (i.e., smuggling via maritime containers); (4) the stated objective of terrorist organizations, such as al Qaeda, of disrupting the U.S. economy and attacking its infrastructure; and (5) the judgment that certain weapons, specifically, improvised radiological and chemical explosive devices, would lend themselves to a commercial maritime platform as a delivery system.
Current law requires inspection of all incoming cargo, but only after the secretary of Homeland Security first determines that a one hundred percent screening system has overcome a variety of technological and economic hurdles. And many interested parties have argued that one hundred percent screening is not technologically or economically feasible, at least currently.
Customs and Border Patrol presently uses intelligence and a risk-based strategy to screen information on one hundred percent of cargo before it is loaded onto vessels destined for the United States. All cargo that is identified as high risk is inspected, either at the foreign port or upon arrival in the United States. Of the approximately 11-million ship-carried cargo containers that arrive at US ports each year, between 5 to 6 percent are randomly inspected.
There have been proposals to instrument all inter-modal containers with a suite of Weapons of Mass Destruction (WMD) detectors. These detectors would monitor the containers for the presence of one or more of the following: chemical warfare agents, biological warfare agents, radiological materials, nuclear materials, and explosives, and provide an alarm upon detection of any of these materials. But with millions of containers in use, and a cost per container for adequate instrumentation in the range of hundreds of thousands of dollars, such an approach would be prohibitively expensive.